The year 1947, the aftermath of the war. Life in a small industrial town revolves around the steelworks. The protagonists meet in high school - Dmitrii Lopatkin is teaching physics, Nadezhda is an English teacher, married to the director of the steelworks, general Drozdov. Lopatkin dreams of designing a particular kind of tubes-making machine that promises to revolutionize the steel industry. The two fall in love and Nadezhda leaves her husband for Dmitri, fascinated by his project and taken in by his enthusiasm and devotion to his work. Drozdov seeks revenge by creating impedements for Lopatkin's invention.